The instant invention relates to improvements in devices for changing the mechanical advantage between rotary input and output elements, and more particularly to improvements in hydrokinetic or hydrodynamic torque converters.
Torque converters of the class to which the present invention pertains are disclosed in published German patent application Serial No. 36 34 395 which describes and shows a toroidal torque converter housing serving to accommodate and to be permanently connected to (e.g., of one piece with) a pump, to accommodate a turbine, and to (normally or often) accommodate a stator between the turbine and the pump. The housing of the torque converter which is described in the aforementioned published German patent application is a toroidal structure having a circular (round) meridian cross-sectional outline. A meridian section includes the common rotational axis of the stator and/or turbine and pump.
Published German patent application Serial No. 35 39 705 discloses a torque converter wherein the toroidal structure has a meridian cross-sectional outline in a plane including the common rotational axis of the turbine and the pump, and the outline is symmetrical with reference to the so-called normal axis, namely an axis located in the meridian plane and normal to the common rotational axis of the aforementioned constituents of the apparatus.
A drawback of hydrokinetic torque converters of the type disclosed in the published German patent applications is that, if the designer is called upon to deliver a torque converter having a bulk wherein the radial dimension (as measured along the normal axis at right angles to the common rotational axis) cannot exceed a predetermined value, the axial length of the torque converter (namely as measured in the direction of the common rotational axis of the pump and turbine) is, or is likely to be, excessive. On the other hand, if the space which is available in the axial direction of the torque converter is rather limited, the required radial diensions of the torque converter (in the direction of the common rotational axis of the pump and turbine) are often excessive.
Another drawback of certain hydrokinetic torque converters (including those specifically referred to hereinbefore) is that the losses, particularly at a relatively low RPM and at the brake locking point, are too prononced. This entails excessive fuel consumption and/or a low torque conversion when the torque converter is utilized in a motor vehicle, especially in a motor vehicle (such as a passenger car) wherein the power train comprises an automatic or an automated change-speed transmission. Thus, there exists an urgent need for hydrokinetic torque converters wherein the dimensions of the rotary housing for the pump, for the turbine, and also (if provided) for the stator can be caused to readily conform to the space which is available (e.g., under the hood of a motor vehicle) without adversely affecting the fuel consumption and/or the torque conversion when the torque converter is in actual use.
The subject matter of the entire commonly owned German priority patent application Serial No. 198 45 718.9 (filed Oct. 5, 1999) is incorporated herein by reference.
Furthermore, this patent application herewith incorporates by reference each and every United States, German and other pending or published patent application, Letters Patent and/or any other publication (such as a Utility Model or Design Letters Patent) which adequately describes and/or shows hydrokinetic torque converters adapted to be redesigned to embody the present invention, to be perused to enhance the understanding of our improved hydrokinetic torque converter and/or to be combined with the improved hydrokinetic torque converter for the purpose of jointly constituting a power train in a motor vehicle or in other arrangements or apparatus which normally employ a torque converter or whose operation and/or efficiency and/or other desirable characteristics can be enhanced as a result of the incorporation of our improved hydrokinetic torque converter therein, as long as such publication(s) is(are) identified in this specification.